I think that what you saw is the perfect example of how you can use fb as a platform to help her learn some social skills and to have good conversations about why people act the way they do.

DD is not ready. She has to first learn accept that lying and going along because she wants to be liked is not the way forward. Sure, it will probably serve her in the short-term but I don't believe in this quick-fix mentality.
I'm sure her day will come that she is ready for the social highway that is facebook but we got a long way to go yet.

I am only trying to point out that if you have a child who inappropriately uses justification to get around rules they don't like, allowing an account on FB might send mixed messages. If a parent here has a problem with giving FB inaccurate information so their child can get on it - since they know their kid better than I do - I support them in doing so.